The chemistry of the structural proteins in the vitreous of humans, cows and rabbits will be studied. Particular attention will be given to the types of collagen present in these extracellular matrices and the relationship of collagen to other structural glycoproteins. Studies will be carried out to determine the types of cross-linking amino acids in bovine vitreous collagen. Intravitreal scar formation will also be studied in vivo in rabbits. The chemical structure of collagen present in the scar tissue will be examined and compared to collagen structures present in the uninjured vitreous. Experiments concerned with the mechanism of scar tissue formation induced in rabbits by a penetrating injury will be carried out using microscopic and autoradiographic techniques.